How to make a moving emission shader?
Try something like this. All I did was separate the Z value of the object's vector, and run it through a Wave texture (scaled really small so it's a single band), and then control it's size even further with a ColorRamp, and it's position with a Mapping Node.
To change the position of the ring (in realtime), I used a Value Node with the value set to #frame (just type it in the box) - this makes the value change with the frame number when you animate. To control the up/down motion of the ring, I used a Math Node set to sine, as it will return a value that cycles between -1 and 1 as the input (frame number) increases. I connected this to the location input of the mapping node (which only affects the Z axis, due to the separation of axes beforehand).
The other math nodes that are there are to slow down the speed of the up down motion (Divide), and to change it's up and down range (Multiply) - you may need to adjust these values based on your preference and/or the size of your object.
Lastly I used this &quot;moving ring&quot; as a mask between my normal material and an Emission Shader: